Computer systems may include interactive software tools that provide environments for designing and executing digital models of electrical, electronic or mechanical devices prior to producing actual physical devices. The design and execution of a target system is performed on computers using the software tools, such as Simulink® and MATLAB®, both from The MathWorks Inc. of Natick, Mass.
Various classes of block diagrams describe computations that can be performed on application specific computational hardware, such as a computer, microcontroller, FPGA, and custom hardware. Classes of such block diagrams include time-based block diagrams such as those found within Simulink from the MathWorks, Inc. of Natick Mass., state-based and flow diagrams such as those found within Stateflow® from the MathWorks, Inc. and data-flow diagrams. A common characteristic among these various forms of block diagrams is that they define semantics on how to execute the diagram.
Historically, engineers and scientists have utilized time-based block diagram models in numerous scientific areas such as Feedback Control Theory and Signal Processing to study, design, debug, and refine dynamic systems. Dynamic systems, which are characterized by the fact that their behaviors change over time, are representative of many real-world systems. Time-based block diagram modeling has become particularly attractive over the last few years with the advent of software packages such as Simulink from The MathWorks, Inc. Such packages provide sophisticated software platforms with a rich suite of support tools that makes the analysis and design of dynamic systems efficient, methodical, and cost-effective.
A dynamic system (either natural or man-made) is a system whose response at any given time is a function of its input stimuli, its current state, and the current time. Such systems range from simple to highly complex systems. Physical dynamic systems include a falling body, the rotation of the earth, bio-mechanical systems (muscles, joints, etc.), bio-chemical systems (gene expression, protein pathways), weather and climate pattern systems, etc. Examples of man-made or engineered dynamic systems include: a bouncing ball, a spring with a mass tied on an end, automobiles, airplanes, control systems in major appliances, communication networks, audio signal processing, nuclear reactors, a stock market, etc. Professionals from diverse areas such as engineering, science, education, and economics build mathematical models of dynamic systems in order to better understand system behavior as it changes with the progression of time. The mathematical models aid in building “better” systems, where “better” may be defined in terms of a variety of performance measures such as quality, time-to-market, cost, speed, size, power consumption, robustness, etc. The mathematical models also aid in analyzing, debugging and repairing existing systems (be it the human body or the anti-lock braking system in a car). The models may also serve an educational purpose of educating others on the basic principles governing physical systems. The models and results are often used as a scientific communication medium between humans. The term “model-based design” is used to refer to the use of block diagram models in the development, analysis, and validation of dynamic systems.
Engineers, analysts, and researchers in the aerospace and aeronautic industry are often faced with relatively small budgets when designing aerospace and aeronautic systems, such as aircraft, spacecraft, missiles, satellites, weapons, and unmanned airborne vehicles (UAVs). Computer-based modeling and execution systems are useful in the design of the aerospace and aeronautic systems, which demand high cost to design and execute real systems. Moreover, automatic code generation facilities support the implementation effort to arrive at embedded code for production and rapid prototype testing. Among aerospace and aeronautic components, a planetary environment is a key element in the design of the aerospace and aeronautic systems.
Conventional modeling and execution systems provide component models and utilities to develop and integrate aerospace and aeronautic systems which include equations of motion models and planetary environment models for atmosphere and wind. The models provided in the conventional modeling and execution systems are limited to standard day atmosphere models, continuous wind turbulence models, and fixed mass equations of motion models. For more accurate design and execution of an aerospace or aeronautic system, non-standard day atmosphere models, discrete wind turbulence models, and variable mass equations of motion models are needed.
Furthermore, in the conventional systems, it is required to replace an atmosphere model to change between atmosphere models, to replace a wind turbulence model to change between wind turbulence models, and to replace equations of motion model to change between equations of motion models. Therefore, there is also a need to conveniently change a currently incorporated atmosphere model, wind turbulence model, or equations of motion model to another atmosphere model, wind turbulence model, or equations of motion model.